1. Technical Field
The present invention relates to an analog-to-digital conversion apparatus that corrects digital data output from a plurality of analog-to-digital conversion sections and a recording medium.
2. Related Art
Conventionally, in case of converting an analog signal into an digital signal, there is known an N-phase (N-way) interleaved analog-to-digital conversion method using N analog-to-digital converters (hereinafter, referred to as ADCs) in order to raise a sampling rate apparently.
However, in the interleaved analog-to-digital conversion method as described above, when some errors are observed in phases of sampling clocks being supplied to each of ADCs and a frequency characteristic of each of ADCs, a frequency spectrum of a digital signal cannot be computed with high precision.
For example, phases of sampling clocks being supplied to each of ADCs have to be different from one another by a predetermined phase. However, it is difficult to move a phase of each of sampling clocks by a predetermined phase precisely. Moreover, although sampling clocks are supplied to each of ADCs with a precise phase, when a frequency characteristic of ADC is not ideal, a variation is observed in sampling timing and a gain in each of ADCs and thus it is difficult to compute a frequency spectrum of a digital signal with high precision.
For this reason, it is necessary to correct the sampled digital signal according to a frequency characteristic of each ADC. For example, a method for correcting a spectrum transformed from the digital signal by way of discrete Fourier transform according to a frequency characteristic of each ADC is considered.
In this case, an arithmetic section that conducts discrete Fourier transform and correction arithmetic sequentially acquires digital signal data by a predetermined data number and performs arithmetic processing. However, since the digital signal data are separately processed, there has been a problem that it is not possible to hold a continuity of a waveform of a digital signal.